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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 | // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2021 Facebook */ #include <linux/stddef.h> #include <linux/bpf.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h> #include <../../../tools/include/linux/filter.h> #include <linux/btf.h> char _license[] SEC("license") = "GPL"; struct args { __u64 log_buf; __u32 log_size; int max_entries; int map_fd; int prog_fd; int btf_fd; }; #define BTF_INFO_ENC(kind, kind_flag, vlen) \ ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ BTF_INT_ENC(encoding, bits_offset, bits) static int btf_load(void) { struct btf_blob { struct btf_header btf_hdr; __u32 types[8]; __u32 str; } raw_btf = { .btf_hdr = { .magic = BTF_MAGIC, .version = BTF_VERSION, .hdr_len = sizeof(struct btf_header), .type_len = sizeof(__u32) * 8, .str_off = sizeof(__u32) * 8, .str_len = sizeof(__u32), }, .types = { /* long */ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 64, 8), /* [1] */ /* unsigned long */ BTF_TYPE_INT_ENC(0, 0, 0, 64, 8), /* [2] */ }, }; static union bpf_attr btf_load_attr = { .btf_size = sizeof(raw_btf), }; btf_load_attr.btf = (long)&raw_btf; return bpf_sys_bpf(BPF_BTF_LOAD, &btf_load_attr, sizeof(btf_load_attr)); } SEC("syscall") int bpf_prog(struct args *ctx) { static char license[] = "GPL"; static struct bpf_insn insns[] = { BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), BPF_LD_MAP_FD(BPF_REG_1, 0), BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; static union bpf_attr map_create_attr = { .map_type = BPF_MAP_TYPE_HASH, .key_size = 8, .value_size = 8, .btf_key_type_id = 1, .btf_value_type_id = 2, }; static union bpf_attr map_update_attr = { .map_fd = 1, }; static __u64 key = 12; static __u64 value = 34; static union bpf_attr prog_load_attr = { .prog_type = BPF_PROG_TYPE_XDP, .insn_cnt = sizeof(insns) / sizeof(insns[0]), }; int ret; ret = btf_load(); if (ret <= 0) return ret; ctx->btf_fd = ret; map_create_attr.max_entries = ctx->max_entries; map_create_attr.btf_fd = ret; prog_load_attr.license = (long) license; prog_load_attr.insns = (long) insns; prog_load_attr.log_buf = ctx->log_buf; prog_load_attr.log_size = ctx->log_size; prog_load_attr.log_level = 1; ret = bpf_sys_bpf(BPF_MAP_CREATE, &map_create_attr, sizeof(map_create_attr)); if (ret <= 0) return ret; ctx->map_fd = ret; insns[3].imm = ret; map_update_attr.map_fd = ret; map_update_attr.key = (long) &key; map_update_attr.value = (long) &value; ret = bpf_sys_bpf(BPF_MAP_UPDATE_ELEM, &map_update_attr, sizeof(map_update_attr)); if (ret < 0) return ret; ret = bpf_sys_bpf(BPF_PROG_LOAD, &prog_load_attr, sizeof(prog_load_attr)); if (ret <= 0) return ret; ctx->prog_fd = ret; return 1; } |